Question: Figure $ABCD$ is a square. Inside this square three smaller squares are drawn with side lengths as labeled. What is the area of the shaded $\text L$-shaped region? [asy]
/* AMC8 2000 #6 Problem */
draw((0,0)--(5,0)--(5,5)--(0,5)--cycle);
draw((1,5)--(1,1)--(5,1));
draw((0,4)--(4,4)--(4,0));
fill((0,4)--(1,4)--(1,1)--(4,1)--(4,0)--(0,0)--cycle);
label("$A$", (5,5), NE);
label("$B$", (5,0), SE);
label("$C$", (0,0), SW);
label("$D$", (0,5), NW);
label("1",(.5,5), N);
label("1",(1,4.5), E);
label("1",(4.5,1), N);
label("1",(4,.5), E);
label("3",(1,2.5), E);
label("3",(2.5,1), N);
[/asy]
Answer: The $\text L$-shaped region is made up of two rectangles with area $3\times 1=3$ plus the corner square with area $1\times 1=1,$ so the area of the $\text L$-shaped figure is $2\times 3+1=\boxed{7}.$

OR

$\text{Square }FECG-\text{Square }FHIJ=4\times 4-3\times 3 =16-9=\boxed{7}.$

OR

The $\text L$-shaped region can be decomposed into a $4\times 1$ rectangle and a $3\times 1$ rectangle. So the total area is $\boxed{7}.$